What is open
One question is holding up most of the others.
The routes page says where each approach stands. The experiments page says what it would cost to settle things. Neither says which answer unblocks which route, so this page does.
The question everything else waits on
Does the broken copy stay inside the cell, or does it reach the surface and interfere with the working one? The measured current is 31.3 percent of what two working copies would give, against 45.8 percent for a copy that simply fails. Those 15 percentage points are the whole question, and the standard assay cannot separate the two explanations even in principle, because they predict the same current.
This matters beyond one variant. If the broken copy interferes, the target is the whole class of changes in this gene that suppress their healthy partner. If it simply sits out, that class does not exist and several routes below lose their rationale rather than their funding.
What is blocked, and by what
Every route still open is held up by something specific. None of these is a shortage of effort, and none is waiting on an idea.
Blocked byDelivery to human heart muscle at the efficiency seen in mice is unproven, and nothing has been tested in a cell.
What would decide itEditing detected at MSH6, a DNA repair gene, would end this design at any efficiency.
Blocked byPublished cardiac efficiency is roughly nine times below the base-editing precedent, and far below the 60 percent that mattered.
What would decide itAny peer-reviewed cardiac prime-editing result at or above 60 percent correction would flip this ranking.
Blocked byHeart muscle carries almost the least of the enzyme the whole approach borrows, ranking 53rd of 54 human tissues.
What would decide itMeasuring the enzyme as protein rather than message in human heart cells could rescue this route, and is the cheapest experiment available.
Blocked byNo target is defined and no assay exists. It waits entirely on the mechanism experiment.
Blocked byThis change is the hardest possible class to tell apart from the healthy copy.
Blocked byThe gene is 6,048 letters of coding sequence against roughly 4,700 that the standard delivery vehicle carries.
Blocked byNeither treats the disease. A device stops an arrhythmia after it starts.
What is already closed
2 of the nine routes are shut, and they are not waiting on anything. Each was closed by a measurement rather than by losing interest, and the measurement is named on the routes page. A closed route is a result: it is one fewer thing for the next person to try.
The two exits
Both are ordinary laboratory work for a group already equipped, and both are written up so that someone else could run them without asking anything further.
What it needsA molecular biology bench, and nothing else. No electrophysiologist and no stem cells are required, which is the main reason this is the easier favour to ask.
What it needsA patch clamp rig and an electrophysiologist for roughly 34 recording days. That time, not the reagents, is the real cost, and it is excluded from the figure above.
What is not blocked
Two results stand on their own and need nothing from the question above. The measurement of a public database, which concerns every gene in it rather than this variant, has its own page. The off-target counting method holds for any base-editing target. Both are published with permanent identifiers.
If you can move any of this
The bottleneck is not analysis. It is that the deciding experiment needs a bench, and this project does not have one. If you have one, or know someone who does, that is the single most useful thing anyone reading this could offer: ethan@brugada.net.